Radial aircraft tires feature a flexible casing which is constructed
of rubber coated ply cords which extend to the beads and are substantially
at 90 degrees to the center line of the tread. The casing is stabilized
by an essentially inextensible circumferential belt.
.
Tread
The tread is made of rubber, compounded for toughness, durability
and tread wear. The tread pattern is designed in accordance with
aircraft operational requirements. The circumferential ribbed tread
is widely used today to provide good traction under varying runway
conditions.
.
Sidewall
The sidewall is a protective layer of flexible, weather-resistant
rubber covering the outer casing ply, extending from tread edge
to bead area.
.
Tread Reinforcing Ply
Tread reinforcement is one or more layers of rubber coated fabric
that strengthen and stabilize the tread area for high-speed operation.
This also serves as a reference for the buffing process in retreadable
tires.
.
Buff Line Cushion
The buff line cushion is made of rubber compounded to enhance the
adhesion between the tread reinforcing ply and the overlay. This
rubber layer is of sufficient thickness to allow for the removal
of the old tread when the tire is retreaded.
.
Overlay
The overlay is a layer of reinforcing rubber-coated fabric placed
on top of the belts to aid in high speed operation.
.
Belt Plies
This is a composite structure which stiffens the tread area for
increased landings. The belt plies increase the tire strength in
the tread area.
.
Casing Plies
Casing plies are layers of rubber-coated fabric which run radially
from bead to bead. The casing plies provide the tire strength in
the sidewall area.
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.
Wire Beads
The beads are hoops of high tensile strength steel wire which anchor
the casing plies and provide a firm mounting surface on the wheel.
.
Apex Strip
The apex strip is a wedge of rubber affixed to the top of the bead
bundle.
.
Chippers
The chippers are layers of rubber-coated fabric applied at a diagonal
angle which improves the durability of the tire in the bead area.
.
Ply Turnups
Casing plies are anchored by wrapping them under the wire beads,
thus forming the ply turnups.
.
Bead Toe
The bead toe is the inner bead edge closest to the tire center line.
.
Bead Heel
The bead heal is the outer bead edge that fits against the wheel
flange.
.
Liner
In tubeless tires, this inner layer of low permeability rubber acts
as a built-in tube and restricts gas from defusing into the casing
plies. For tube-type tires, a thinner rubber liner is used to prevent
tube chafing against the inside ply.
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Courtesy
of The Goodyear Tire & Rubber Company
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